The most popular websites in the world are daily standbys for millions, if not billions, of people. Sites like Google, Facebook, Twitter, eBay, and YouTube provide services and entertainment that, for many of the world’s citizens, can be enjoyed without forethought or any difficulty that goes beyond a reliable Internet connection.

However, in some countries and regions, these popular sites aren’t just difficult to access, they’re also banned. Here is a look at some of the world’s most popular websites and the reasons and rationale behind why some countries have banned them.

Google

The most popular website in the world, Google processes almost 12 billion searches a month. In the United States, it enjoys over 85 percent of the search market, and throughout the rest of the world, it’s considerably more popular than its closest competitors — except, of course, where it’s banned. The vast majority of countries that ban or restrict Google do so in order to keep a tight rein on what they consider to be “dangerous” websites, and Google — because it’s the gate through which people pass on their way to these sites — is censored accordingly.

“Dangerous,” of course, is in the eye of the beholder. What’s considered a problem in Turkey is different than in Iran or China. From pornography to feminist sites to news sources that aren’t state sanctioned to social media sites where citizens may criticize or expose their government, some countries would rather keep Google on lock down than risk their citizenry’s exposure to certain ideas, opportunities, and images. People in these places must access banned sites like Google via alternate means.

Facebook

Facebook’s ubiquity and seemingly facile raison d’être makes banning it seem overzealous. After all, what’s so troubling about staying in touch with high school classmates and watching the cat videos your aunt posts? Nothing. But if you live in a country with a government that isn’t keen on negative press or the sometimes damning results of people freely expressing themselves, Facebook’s easy to use platform is suddenly revealed as not that innocuous. Anti-government rants are easy to post on walls, and implicating and hard-to-refute videos uploaded to the popular site can be shared around the world in a mere matter of minutes. For countries with an interest in keeping the peace by controlling what information is allowed to see the light of day — think: Iran, China, Vietnam — Facebook poses much too large a threat to be allowed to operate.

Twitter

One of the most popular sites to ban, Twitter is a great example of how the pen can be mightier than the sword, except in its case, the “pen” occupies a mere 140-character area. Twitter’s social power — and the reason it gets banned — is due to its hashtags, which allow users to easily find, come alongside, promote, and keep track of movements.

From Boko Haram’s kidnapping of 273 girls and the resulting solidarity hashtag #BringBackOurGirls that placed pressure on the Nigerian government and the world’s governments to act on the kidnapped girls’ behalf to Twitter’s role in accelerating Egypt’s uprising, when it comes to a government trying to contain a situation (or make it go away) or trying to keep a restless and unhappy population from revolt, Twitter is an absolute nightmare.

Youtube

Another favorite among the Web-censoring nations, YouTube is banned in places as far-reaching as Eritrea, Pakistan, Iran, Germany, and Turkey, which for the Web’s third most popular site, only seems to boost its importance. Interestingly, the reasons YouTube gets banned aren’t always due to political or religious concerns, although these reasons are, by far, the most common. Here are some of the reasons YouTube may find itself on the receiving end of a ban:

To limit citizens’ exposure to video that may cause unrest

To prevent government or religious criticism

To keep from violating copyright laws

To stop violations of morality- and ethics-based laws

National security concerns

To protect children from seeing content intended for adults

To reduce overuse of network bandwidth

YouTube is also the website most likely to be blocked at workplaces or schools, but in these contexts, it’s mostly in an attempt to reduce distractions.

Banning the Internet’s most popular websites isn’t common practice for every country, but it’s common enough to affect over 1 billion people on a daily basis. Whether or not those bans will continue to hold remains to be seen, but more and more, people desire and expect a certain measure of freedom when it comes to the Internet — and to their daily lives.